How to disable swapping in Elasticsearch on Kubernetes?

问题

As per the official es docs, disabling swapping is one of the best performance boosts available to Elasticsearch.

However, it's proving to be difficult to configure. I've spent a number of hours researching and attempting different methods to disable swapping using the official ES docker image on Kubernetes.

When setting bootstrap.memory_lock: true as an env variable, the image fails to boot up with the error: Unable to lock JVM Memory: error=12, reason=Cannot allocate memory. This can result in part of the JVM being swapped out. Increase RLIMIT_MEMLOCK, soft limit: 65536, hard limit: 65536. As the docs point out, this is kind of expected. I've even mounted a custom /etc/security/limits.conf with the settings, but that's failed.

What is the recommended way to disable swapping when using the official es image on k8s?

And, here are the relevant sections of my yaml

apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: elastic-data
spec:
  serviceName: elastic-data
  replicas: 1
  template:
    spec:
      securityContext:
        runAsUser: 0
        fsGroup: 0
      containers:
      - name: elastic-data
        image: docker.elastic.co/elasticsearch/elasticsearch-oss:6.4.0
        env:
        - name: ES_JAVA_OPTS
          value: "-Xms2g -Xmx2g"
        - name: cluster.name
          value: "elastic-devs"
        - name: node.name
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: discovery.zen.ping.unicast.hosts
          value: "elastic-master.default.svc.cluster.local"
        - name: node.master
          value: "false"
        - name: node.ingest
          value: "false"
        - name: node.data
          value: "true"
        - name: network.host
          value: "0.0.0.0"
        - name: path.data
          value: /usr/share/elasticsearch/data
        - name: indices.memory.index_buffer_size
          value: "512MB"
        - name: bootstrap.memory_lock
          value: "true"
        resources:
          requests:
            memory: "3Gi"
          limits:
            memory: "3Gi"
        ports:
        - containerPort: 9300
          name: transport
        - containerPort: 9200
          name: http
        volumeMounts:
        - name: data-volume
          mountPath: /usr/share/elasticsearch/data
        - name: swappiness-config
          mountPath: /etc/security/limits.conf
          subPath: limits.conf
      volumes:
      - name: data-volume
        persistentVolumeClaim:
          claimName: pvc-es
     - name: swappiness-config
       configMap:
         name: swappiness-config
         items:
          - key: limits.conf
             path: limits.conf

limits.conf

elasticsearch soft memlock unlimited
elasticsearch hard memlock unlimited
elasticsearch hard nofile 65536
elasticsearch soft nofile 65536

回答1:

I think, the ulimits in my yaml weren't being recognized, so I followed this post and created an image with a custom entrypoint that set the settings.

回答2:

Which image-type are you using? If its Container-Optimized OS (cos) try to switch to Ubuntu based images

来源：https://stackoverflow.com/questions/52123756/how-to-disable-swapping-in-elasticsearch-on-kubernetes